I totally understand how you feel, I’ve been there.
If you are not up to going to PT tomorrow, cancel the appointment. You don’t have to go to every appointment they make. They make too many for us, anyway. After the busy day you had today (that was full of natural PT) you’d be wise to stay home tomorrow and rest.
Don’t worry about the leg lifts. I refused to do them because they hurt my lower back. It took several weeks but eventually I could get my leg up on my elevating wedge by myself. It took me a long time to realize that I was actually doing a leg lift when I put my leg on the wedge!
And it happened without my “working on it!”
Your knee/leg will come along fine if you just relax and accept it as it is right now, it’s working so hard to heal the onslaught that is knee replacement surgery. PT can be helpful,
if we have the right therapist. But too often we are asked to push our knee beyond it’s current ability. Don’t let your PT do that to you.
Regaining our ROM/quad strength/etc. is more about Time than repetitions of a list of exercises.
Time to recover.
Time for pain and swelling to settle.
Time to heal.
Our range of motion, and other abilities, are right there all along just waiting for that to happen so it can show itself.
In the general run of things, it doesn't need to be fought for, worked hard for or worried about. It will happen. Normal activity is the key to success.